Visualization on full spine radiographs of the anatomical connections of the centres of the segmental body mass supported by each vertebra and measured in vivo.

A gamma-ray scanner has been used to develop in vivo a rapid, noninvasive technique for the estimation of the mass of successive body scans, and the positions of the centres of those masses. The integrated data are computed to calculate the mass supported by each vertebra and the coordinates of the centre of these masses. These coordinates are transferred from the coordinate system of the gamma ray table to the coordinate system of the X-ray radiographs. In this way, the anatomical relations of the centres of these masses are visualized on the frontal and sagittal full spine radiographs. The method allowed the estimation of various biomechanical parameters such as the height of half the body mass or the compressive load on a specific vertebra. These new parameters were found to be similar to equivalent parameters in the literature. Therefore, these comparisons validate the method. Fourteen normal subjects were tested, and their mean data are proposed as reference.